1. Field of the Invention
This invention relates to a portable truck scale and more particularly to a ground-conforming portable truck scale which may be set up quickly for use on surfaces which may not be level.
2. Description of the Related Art
In the past, portable truck scales had to be small enough so as to be truly portable, but a disadvantage of those scales was that they were only able to weigh one or two axles at once, requiring too much time to complete the weighing. The portable truck scales of the past met with some success because they were constructed stiff and strong enough to resist flexing due to the outer frame""s rigidity containing the load cells. This is not practical for manufacture, nor does the same work when weighing full trucks or three axles or more while still being portable. Further, the prior art portable truck scales had to be set up on a level location.
The portable truck scales of the prior art normally utilized electronic weigh cells. In order for the electronic weigh cells to repeat their accuracy they must, when unloaded, have the same tare weight equally on all four cells. To do this, typically, one would have to level all weigh cells so that the rigid supporting truck platform could be equally weighted on the cells. This requires much set-up time, making it only applicable to permanent scales, located and monumentally placed.
A ground-conforming portable truck scale is disclosed which may be positioned on the ground for weighing a truck and then raised therefrom to a transport position. The portable truck scale of this invention comprises first and second side truss members having a forward end, a rearward end, an upper end, and a lower end. The first and second side truss members are horizontally spaced-apart with each of the first and second side truss members having a plurality of spaced-apart openings formed therein along the lengths thereof which receive the ends of cross-beams extending between the first and second side truss members. A center pivot beam, having opposite ends, extends between the first and second side truss members at the approximate center length thereof with the opposite ends of the center pivot beam being pivotally secured, about a horizontal axis, to the first and second side truss members. A front ramp is pivotally secured to the forward ends of the first and second side truss members with the front ramp being pivotally secured to the first and second side truss members about a horizontal axis which is transverse to the length of the first and second side truss members and which is spaced rearwardly from the forward ends thereof. The front ramp is also pivotally secured to the forward ends of the first and second side truss members about a horizontal axis which is parallel to the length of the first and second side truss members. A tow hitch is secured to the first ramp for connection to a prime mover when the scale is in its transport position. A rear ramp is pivotally secured to the rearward ends of the first and second side truss members about a horizontal axis which is transverse to the length of the first and second side truss members and which is spaced forwardly from the rearward ends thereof. The rear ramp is also pivotally secured to the rearward ends of the first and second side truss members about a horizontal axis which is parallel to the length of the first and second side truss members. A wheel assembly is operatively connected to the rear ramp for supporting the rear ramp and the rearward ends of the first and second side truss members above the ground when the scale is in its transport position. A front lift jack assembly is operatively secured to the front ramp for raising the front ramp from a ground-engaging position to a transport position and for lowering the front ramp from its transport position to its ground-engaging position. A rear lift jack assembly is operatively secured to the rear ramp for raising the rear ramp from a ground-engaging position to a transport position and for lowering the rear ramp from its transport position to its ground-engaging position. Weigh (load) cells are operatively connected to the forward and rearward ends of each of the first and second side truss members. The weigh cells at the forward ends of the side truss members are positioned between the ends of the side truss members and the front ramp. The weigh cells at the rearward ends of the side truss members are positioned between the ends of the side truss members and the rear ramp.
It is a principal object of the invention to provide a ground-conforming portable truck scale.
A further object of the invention is to provide a ground-conforming portable truck scale which may be utilized on uneven ground.
A further object of the invention is to provide a ground-conforming portable truck scale which provides a rigid platform scale which may be towed, but which provides equal distribution of weight at different angles of level.
A further object of the invention is to provide a portable truck scale of the type described which has ramps at the forward and rearward ends thereof.
Still another object of the invention is to provide a ground-conforming portable truck scale which is quickly and easily set-up, regardless of the level of the ground conditions.
Still another object of the invention is to provide a ground-conforming portable truck scale which provides equal distribution of weight to four weigh cells at different angles of level.
Still another object of the invention is to provide a portable truck scale of the type described which is economical of manufacture, durable in use and refined in appearance.
These and other objects of the invention will be apparent to those skilled in the art.